title: Retrospective study of predictors of bone metastasis in prostate cancer cases.
abstract: BACKGROUND
  The purpose of this study was to identify clinical profiles of patients with low risk of having bone metastases, for which bone scanning could be safely eliminated.
  
  
  METHODS
  This retrospective cross sectional study looked at prostate cancer patients seen in the Urology Departments in 2 tertiary centres over the 11 year period starting from January 2000 to May 2011. Patient demographic data, levels of PSA at diagnosis, Gleason score for the biopsy core, T-staging as well as the lymph node status were recorded and analysed.
  
  
  RESULTS
  258 men were included. The mean age of those 90 men (34.9%) with bone metastasis was 69.2 ± 7.3 years. Logistic regression found that PSA level (P=0.000) at diagnosis and patient's nodal-stage (P=0.02) were the only two independent variables able to predict the probability of bone metastasis among the newly diagnosed prostate cancer patients. Among those with a low PSA level less than 20 ng/ml, and less than 10 ng/ml, bone metastasis were detected in 10.3% (12 out of 117) and 9.7% (7 out of 72), respectively. However, by combining PSA level of 10 ng/ml or lower, and nodal negative as the two criteria to predict negative bone scan, a relatively high negative predictive value of 93.8% was obtained. The probability of bone metastasis in prostate cancer can be calculated with this formula: -1.069+0.007(PSA value, ng/ml) +1.021(Nodal status, 0 or 1)=x Probability of bone metastasis=2.718 x/1+2.718 x.
  
  
  CONCLUSIONS
  Newly diagnosed prostate cancer patients with a PSA level of 10 ng/ml or lower and negative nodes have a very low risk of bone metastasis (negative predictive value 93.8%) and therefore bone scans may not be necessary.
authors.affiliation: Urology Unit, Department of Surgery, Universiti Kebangsaan Malaysia Medical Centre, Kuala Lumpur, Malaysia. chrisckho2002@yahoo.com
authors.forename: Christopher Chee Kong
authors.initials: CC
authors.lastname: Ho
authors.forename: Poh Keat
authors.initials: PK
authors.lastname: Seong
authors.forename: Zulkifli Md
authors.initials: ZM
authors.lastname: Zainuddin
authors.forename: Mohd Rizal
authors.initials: MR
authors.lastname: Abdul Manaf
authors.forename: Muhilan
authors.initials: M
authors.lastname: Parameswaran
authors.forename: Azad H A
authors.initials: AH
authors.lastname: Razack
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001859:Bone Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000556:secondary*; D001842:Bone and Bones / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000473:pathology*; D011859:Radiography; D012189:Retrospective Studies
chemical_list: D017430:Prostate-Specific Antigen